tune up speck on a 86 cj7
11-08-2003, 11:40 PM
#31
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
It's convoluted a bit... ;-)
You want the spark to fire in 'advance' of the piston hitting Top Dead
Center or Before it, so going BTDC is advancing the spark.
I want a stable idle 'advanced' at 9 degrees 'before top dead center'
with no advance mechanism at all turned on, just where the distributor
base sets.
To pass emissions this way, the carb needs to be leaned a bit so the
engine has a rumble to it. If it is purring, it is running too rich for
the sniffer. I split the difference after the test.
'Ported' vacuum has no pull with the throttle closed. It sucks from
above the plate. On the BBD it is near the top on the valve cover side
and front bottom fender side one too I think.
'Manifold' vacuum has full pull with the throttle closed. It sucks
below the carb.
Having the timing advanced at idle will make a lean idle setting on the
carb purr, so emissions call for it. It loses the vacuum when you punch
it and starts off slowly/sluggish until the centripetal weights start to
kick in up in the teens for rpm.
With ported, I get full advance instantly and if I punch it off the line
it will light up my 33" muds with 3.31 gears turning them.
With ported, the 'advance' advances the timing spark to 'more' advanced
before top dead center, not advancing above 0 but advancing backward
before 0.
Basically you sacrifice a bit smoother idle for instant punch and a
little more noise. I like the noise, it sounds cool coming down
something steep in gear with the throttle closed. If you are old enough
to remember muscle cars, they had this 'burble pop pop' sound when the
engine was doing the braking, same sound.
Mike
TJim wrote:
>
> Mike, How do you convert to ported vacuum? They pull in opposite
> directions. Do you go to port and compensate with the distributor position?
> I would think the increase in vacuum on throttle would retard your
> distributor when you need it to be advancing... ?
>
> --
> Jim
> --
> 98 TJ SE
> 90 SJ GW
> http://www.delawareja.com/gallery/JDJeep98
> "You can do any job in the world with the wrong tool if you try hard
> enough..."
> "4x4" in caps is "$X$"
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
You want the spark to fire in 'advance' of the piston hitting Top Dead
Center or Before it, so going BTDC is advancing the spark.
I want a stable idle 'advanced' at 9 degrees 'before top dead center'
with no advance mechanism at all turned on, just where the distributor
base sets.
To pass emissions this way, the carb needs to be leaned a bit so the
engine has a rumble to it. If it is purring, it is running too rich for
the sniffer. I split the difference after the test.
'Ported' vacuum has no pull with the throttle closed. It sucks from
above the plate. On the BBD it is near the top on the valve cover side
and front bottom fender side one too I think.
'Manifold' vacuum has full pull with the throttle closed. It sucks
below the carb.
Having the timing advanced at idle will make a lean idle setting on the
carb purr, so emissions call for it. It loses the vacuum when you punch
it and starts off slowly/sluggish until the centripetal weights start to
kick in up in the teens for rpm.
With ported, I get full advance instantly and if I punch it off the line
it will light up my 33" muds with 3.31 gears turning them.
With ported, the 'advance' advances the timing spark to 'more' advanced
before top dead center, not advancing above 0 but advancing backward
before 0.
Basically you sacrifice a bit smoother idle for instant punch and a
little more noise. I like the noise, it sounds cool coming down
something steep in gear with the throttle closed. If you are old enough
to remember muscle cars, they had this 'burble pop pop' sound when the
engine was doing the braking, same sound.
Mike
TJim wrote:
>
> Mike, How do you convert to ported vacuum? They pull in opposite
> directions. Do you go to port and compensate with the distributor position?
> I would think the increase in vacuum on throttle would retard your
> distributor when you need it to be advancing... ?
>
> --
> Jim
> --
> 98 TJ SE
> 90 SJ GW
> http://www.delawareja.com/gallery/JDJeep98
> "You can do any job in the world with the wrong tool if you try hard
> enough..."
> "4x4" in caps is "$X$"
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
11-09-2003, 09:10 AM
#32
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
mike romain said."I think you have to figure or I do anyway that the advance
should match
the 'sweet spot' on the power curve".
my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
that is where I shift if I am accelerating. so with that in mind should I
install the weaker centrifugal springs(Mr. gasket part # 925d) in the
distributor. carmine
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FAD873F.7063DDE9@sympatico.ca...
> I think you have to figure or I do anyway that the advance should match
> the 'sweet spot' on the power curve.
>
> These long sixes are low rpm engines with a red line of 4500 that can
> only be reached if the emissions computer is dead. It tops around 3500
> with the computer...
>
> My engine gets the best gas mileage at this point too and for me 23-2500
> rpm is where I keep it at 65-70 mph in 4th gear.
>
> I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> off, sometimes ported can suck a bit at idle, I don't take the chance)
> so I get an instant punch when I floor it, then it mellows a bit as the
> mechanical weights take over.
>
> OEM is a manifold vacuum on the timing with the computer adjusting
> things on the 258's after 82. It will jump about 15 degrees when you
> kill the computer and wire the distributor to the ignition module
> direct.
>
> Mike
>
> Red Racer wrote:
> >
> > Hi Mike,
> >
> > If that is the case, Carmine is probably already getting a decent curve.
> > 2300 is pretty quick for a OEM situation, but all the better as "the
quicker
> > the better" is true to an extent. I've worked on many "performance
motors",
> > where the mechanical advance was still advancing past 4 grand. That is
way
> > to slow, even for a stock motor, irregardless of how many cylinders it
has.
> >
> > Rick
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD2064.60008CFE@sympatico.ca...
> > > Bill, someone or several have told me that the 258 tops out the timing
> > > around 2300 rpm.
> > >
> > > Do you know for sure?
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > "L.W.(ßill) ------ III" wrote:
> > > >
> > > > Hi Carmine,
> > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > quicker. I believe you'll be happier with the stock springs,
following
> > > > your horse power curve, reaching full advance around thirty five
hundred
> > > > RPMs. The weaker springs you talk of are for race engines and they
jump
> > > > to full advance by two grand, it has an advantage on the drag strip,
but
> > > > not for Jeepin'. What I believe is perfect timing is a total of
thirty
> > > > eight degrees on the crank. You'll need a special timing light to
check
> > > > for total. Or know exactly what your distributor's specs are.
> > > > God Bless America, ßill O|||||||O
> > > > mailto:-------------------- http://www.----------.com/
> > > >
> > > > Jet wrote:
> > > > >
> > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
ignition
> > and a
> > > > > msd blaster coil. I am wondering what is the tune up speck for my
set
> > up.
> > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
read
> > on a
> > > > > website that when changing to the ford TFI ignition that I could
put
> > > > > different spring (Mr. gasket part # 925d) in the centrifugal
timing
> > advance
> > > > > to get more advance on high rpm's. should I put the different
spring
> > in?
> > > > > anyone have any advice. carmine
should match
the 'sweet spot' on the power curve".
my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
that is where I shift if I am accelerating. so with that in mind should I
install the weaker centrifugal springs(Mr. gasket part # 925d) in the
distributor. carmine
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FAD873F.7063DDE9@sympatico.ca...
> I think you have to figure or I do anyway that the advance should match
> the 'sweet spot' on the power curve.
>
> These long sixes are low rpm engines with a red line of 4500 that can
> only be reached if the emissions computer is dead. It tops around 3500
> with the computer...
>
> My engine gets the best gas mileage at this point too and for me 23-2500
> rpm is where I keep it at 65-70 mph in 4th gear.
>
> I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> off, sometimes ported can suck a bit at idle, I don't take the chance)
> so I get an instant punch when I floor it, then it mellows a bit as the
> mechanical weights take over.
>
> OEM is a manifold vacuum on the timing with the computer adjusting
> things on the 258's after 82. It will jump about 15 degrees when you
> kill the computer and wire the distributor to the ignition module
> direct.
>
> Mike
>
> Red Racer wrote:
> >
> > Hi Mike,
> >
> > If that is the case, Carmine is probably already getting a decent curve.
> > 2300 is pretty quick for a OEM situation, but all the better as "the
quicker
> > the better" is true to an extent. I've worked on many "performance
motors",
> > where the mechanical advance was still advancing past 4 grand. That is
way
> > to slow, even for a stock motor, irregardless of how many cylinders it
has.
> >
> > Rick
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD2064.60008CFE@sympatico.ca...
> > > Bill, someone or several have told me that the 258 tops out the timing
> > > around 2300 rpm.
> > >
> > > Do you know for sure?
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > "L.W.(ßill) ------ III" wrote:
> > > >
> > > > Hi Carmine,
> > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > quicker. I believe you'll be happier with the stock springs,
following
> > > > your horse power curve, reaching full advance around thirty five
hundred
> > > > RPMs. The weaker springs you talk of are for race engines and they
jump
> > > > to full advance by two grand, it has an advantage on the drag strip,
but
> > > > not for Jeepin'. What I believe is perfect timing is a total of
thirty
> > > > eight degrees on the crank. You'll need a special timing light to
check
> > > > for total. Or know exactly what your distributor's specs are.
> > > > God Bless America, ßill O|||||||O
> > > > mailto:-------------------- http://www.----------.com/
> > > >
> > > > Jet wrote:
> > > > >
> > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
ignition
> > and a
> > > > > msd blaster coil. I am wondering what is the tune up speck for my
set
> > up.
> > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
read
> > on a
> > > > > website that when changing to the ford TFI ignition that I could
put
> > > > > different spring (Mr. gasket part # 925d) in the centrifugal
timing
> > advance
> > > > > to get more advance on high rpm's. should I put the different
spring
> > in?
> > > > > anyone have any advice. carmine
11-09-2003, 09:10 AM
#33
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
mike romain said."I think you have to figure or I do anyway that the advance
should match
the 'sweet spot' on the power curve".
my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
that is where I shift if I am accelerating. so with that in mind should I
install the weaker centrifugal springs(Mr. gasket part # 925d) in the
distributor. carmine
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FAD873F.7063DDE9@sympatico.ca...
> I think you have to figure or I do anyway that the advance should match
> the 'sweet spot' on the power curve.
>
> These long sixes are low rpm engines with a red line of 4500 that can
> only be reached if the emissions computer is dead. It tops around 3500
> with the computer...
>
> My engine gets the best gas mileage at this point too and for me 23-2500
> rpm is where I keep it at 65-70 mph in 4th gear.
>
> I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> off, sometimes ported can suck a bit at idle, I don't take the chance)
> so I get an instant punch when I floor it, then it mellows a bit as the
> mechanical weights take over.
>
> OEM is a manifold vacuum on the timing with the computer adjusting
> things on the 258's after 82. It will jump about 15 degrees when you
> kill the computer and wire the distributor to the ignition module
> direct.
>
> Mike
>
> Red Racer wrote:
> >
> > Hi Mike,
> >
> > If that is the case, Carmine is probably already getting a decent curve.
> > 2300 is pretty quick for a OEM situation, but all the better as "the
quicker
> > the better" is true to an extent. I've worked on many "performance
motors",
> > where the mechanical advance was still advancing past 4 grand. That is
way
> > to slow, even for a stock motor, irregardless of how many cylinders it
has.
> >
> > Rick
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD2064.60008CFE@sympatico.ca...
> > > Bill, someone or several have told me that the 258 tops out the timing
> > > around 2300 rpm.
> > >
> > > Do you know for sure?
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > "L.W.(ßill) ------ III" wrote:
> > > >
> > > > Hi Carmine,
> > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > quicker. I believe you'll be happier with the stock springs,
following
> > > > your horse power curve, reaching full advance around thirty five
hundred
> > > > RPMs. The weaker springs you talk of are for race engines and they
jump
> > > > to full advance by two grand, it has an advantage on the drag strip,
but
> > > > not for Jeepin'. What I believe is perfect timing is a total of
thirty
> > > > eight degrees on the crank. You'll need a special timing light to
check
> > > > for total. Or know exactly what your distributor's specs are.
> > > > God Bless America, ßill O|||||||O
> > > > mailto:-------------------- http://www.----------.com/
> > > >
> > > > Jet wrote:
> > > > >
> > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
ignition
> > and a
> > > > > msd blaster coil. I am wondering what is the tune up speck for my
set
> > up.
> > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
read
> > on a
> > > > > website that when changing to the ford TFI ignition that I could
put
> > > > > different spring (Mr. gasket part # 925d) in the centrifugal
timing
> > advance
> > > > > to get more advance on high rpm's. should I put the different
spring
> > in?
> > > > > anyone have any advice. carmine
should match
the 'sweet spot' on the power curve".
my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
that is where I shift if I am accelerating. so with that in mind should I
install the weaker centrifugal springs(Mr. gasket part # 925d) in the
distributor. carmine
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FAD873F.7063DDE9@sympatico.ca...
> I think you have to figure or I do anyway that the advance should match
> the 'sweet spot' on the power curve.
>
> These long sixes are low rpm engines with a red line of 4500 that can
> only be reached if the emissions computer is dead. It tops around 3500
> with the computer...
>
> My engine gets the best gas mileage at this point too and for me 23-2500
> rpm is where I keep it at 65-70 mph in 4th gear.
>
> I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> off, sometimes ported can suck a bit at idle, I don't take the chance)
> so I get an instant punch when I floor it, then it mellows a bit as the
> mechanical weights take over.
>
> OEM is a manifold vacuum on the timing with the computer adjusting
> things on the 258's after 82. It will jump about 15 degrees when you
> kill the computer and wire the distributor to the ignition module
> direct.
>
> Mike
>
> Red Racer wrote:
> >
> > Hi Mike,
> >
> > If that is the case, Carmine is probably already getting a decent curve.
> > 2300 is pretty quick for a OEM situation, but all the better as "the
quicker
> > the better" is true to an extent. I've worked on many "performance
motors",
> > where the mechanical advance was still advancing past 4 grand. That is
way
> > to slow, even for a stock motor, irregardless of how many cylinders it
has.
> >
> > Rick
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD2064.60008CFE@sympatico.ca...
> > > Bill, someone or several have told me that the 258 tops out the timing
> > > around 2300 rpm.
> > >
> > > Do you know for sure?
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > "L.W.(ßill) ------ III" wrote:
> > > >
> > > > Hi Carmine,
> > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > quicker. I believe you'll be happier with the stock springs,
following
> > > > your horse power curve, reaching full advance around thirty five
hundred
> > > > RPMs. The weaker springs you talk of are for race engines and they
jump
> > > > to full advance by two grand, it has an advantage on the drag strip,
but
> > > > not for Jeepin'. What I believe is perfect timing is a total of
thirty
> > > > eight degrees on the crank. You'll need a special timing light to
check
> > > > for total. Or know exactly what your distributor's specs are.
> > > > God Bless America, ßill O|||||||O
> > > > mailto:-------------------- http://www.----------.com/
> > > >
> > > > Jet wrote:
> > > > >
> > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
ignition
> > and a
> > > > > msd blaster coil. I am wondering what is the tune up speck for my
set
> > up.
> > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
read
> > on a
> > > > > website that when changing to the ford TFI ignition that I could
put
> > > > > different spring (Mr. gasket part # 925d) in the centrifugal
timing
> > advance
> > > > > to get more advance on high rpm's. should I put the different
spring
> > in?
> > > > > anyone have any advice. carmine
11-09-2003, 09:10 AM
#34
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
mike romain said."I think you have to figure or I do anyway that the advance
should match
the 'sweet spot' on the power curve".
my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
that is where I shift if I am accelerating. so with that in mind should I
install the weaker centrifugal springs(Mr. gasket part # 925d) in the
distributor. carmine
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FAD873F.7063DDE9@sympatico.ca...
> I think you have to figure or I do anyway that the advance should match
> the 'sweet spot' on the power curve.
>
> These long sixes are low rpm engines with a red line of 4500 that can
> only be reached if the emissions computer is dead. It tops around 3500
> with the computer...
>
> My engine gets the best gas mileage at this point too and for me 23-2500
> rpm is where I keep it at 65-70 mph in 4th gear.
>
> I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> off, sometimes ported can suck a bit at idle, I don't take the chance)
> so I get an instant punch when I floor it, then it mellows a bit as the
> mechanical weights take over.
>
> OEM is a manifold vacuum on the timing with the computer adjusting
> things on the 258's after 82. It will jump about 15 degrees when you
> kill the computer and wire the distributor to the ignition module
> direct.
>
> Mike
>
> Red Racer wrote:
> >
> > Hi Mike,
> >
> > If that is the case, Carmine is probably already getting a decent curve.
> > 2300 is pretty quick for a OEM situation, but all the better as "the
quicker
> > the better" is true to an extent. I've worked on many "performance
motors",
> > where the mechanical advance was still advancing past 4 grand. That is
way
> > to slow, even for a stock motor, irregardless of how many cylinders it
has.
> >
> > Rick
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD2064.60008CFE@sympatico.ca...
> > > Bill, someone or several have told me that the 258 tops out the timing
> > > around 2300 rpm.
> > >
> > > Do you know for sure?
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > "L.W.(ßill) ------ III" wrote:
> > > >
> > > > Hi Carmine,
> > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > quicker. I believe you'll be happier with the stock springs,
following
> > > > your horse power curve, reaching full advance around thirty five
hundred
> > > > RPMs. The weaker springs you talk of are for race engines and they
jump
> > > > to full advance by two grand, it has an advantage on the drag strip,
but
> > > > not for Jeepin'. What I believe is perfect timing is a total of
thirty
> > > > eight degrees on the crank. You'll need a special timing light to
check
> > > > for total. Or know exactly what your distributor's specs are.
> > > > God Bless America, ßill O|||||||O
> > > > mailto:-------------------- http://www.----------.com/
> > > >
> > > > Jet wrote:
> > > > >
> > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
ignition
> > and a
> > > > > msd blaster coil. I am wondering what is the tune up speck for my
set
> > up.
> > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
read
> > on a
> > > > > website that when changing to the ford TFI ignition that I could
put
> > > > > different spring (Mr. gasket part # 925d) in the centrifugal
timing
> > advance
> > > > > to get more advance on high rpm's. should I put the different
spring
> > in?
> > > > > anyone have any advice. carmine
should match
the 'sweet spot' on the power curve".
my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
that is where I shift if I am accelerating. so with that in mind should I
install the weaker centrifugal springs(Mr. gasket part # 925d) in the
distributor. carmine
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FAD873F.7063DDE9@sympatico.ca...
> I think you have to figure or I do anyway that the advance should match
> the 'sweet spot' on the power curve.
>
> These long sixes are low rpm engines with a red line of 4500 that can
> only be reached if the emissions computer is dead. It tops around 3500
> with the computer...
>
> My engine gets the best gas mileage at this point too and for me 23-2500
> rpm is where I keep it at 65-70 mph in 4th gear.
>
> I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> off, sometimes ported can suck a bit at idle, I don't take the chance)
> so I get an instant punch when I floor it, then it mellows a bit as the
> mechanical weights take over.
>
> OEM is a manifold vacuum on the timing with the computer adjusting
> things on the 258's after 82. It will jump about 15 degrees when you
> kill the computer and wire the distributor to the ignition module
> direct.
>
> Mike
>
> Red Racer wrote:
> >
> > Hi Mike,
> >
> > If that is the case, Carmine is probably already getting a decent curve.
> > 2300 is pretty quick for a OEM situation, but all the better as "the
quicker
> > the better" is true to an extent. I've worked on many "performance
motors",
> > where the mechanical advance was still advancing past 4 grand. That is
way
> > to slow, even for a stock motor, irregardless of how many cylinders it
has.
> >
> > Rick
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD2064.60008CFE@sympatico.ca...
> > > Bill, someone or several have told me that the 258 tops out the timing
> > > around 2300 rpm.
> > >
> > > Do you know for sure?
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > "L.W.(ßill) ------ III" wrote:
> > > >
> > > > Hi Carmine,
> > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > quicker. I believe you'll be happier with the stock springs,
following
> > > > your horse power curve, reaching full advance around thirty five
hundred
> > > > RPMs. The weaker springs you talk of are for race engines and they
jump
> > > > to full advance by two grand, it has an advantage on the drag strip,
but
> > > > not for Jeepin'. What I believe is perfect timing is a total of
thirty
> > > > eight degrees on the crank. You'll need a special timing light to
check
> > > > for total. Or know exactly what your distributor's specs are.
> > > > God Bless America, ßill O|||||||O
> > > > mailto:-------------------- http://www.----------.com/
> > > >
> > > > Jet wrote:
> > > > >
> > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
ignition
> > and a
> > > > > msd blaster coil. I am wondering what is the tune up speck for my
set
> > up.
> > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
read
> > on a
> > > > > website that when changing to the ford TFI ignition that I could
put
> > > > > different spring (Mr. gasket part # 925d) in the centrifugal
timing
> > advance
> > > > > to get more advance on high rpm's. should I put the different
spring
> > in?
> > > > > anyone have any advice. carmine
11-09-2003, 12:08 PM
#35
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
I would find a safe stretch of road and time it from stop up to say 60
mph with the stock springs in first, then do the same with the heavier
springs.
I don't know what the RV cam runs like, but to get the advance to come
up slower so it peaks at a higher rpm means you need heavier springs or
lighter weights.
Lighter springs will make the advance peak earlier. The weights work
against the springs to advance the timing. Heavier springs means higher
rpm before the weights can stretch them out.
Mike
Jet wrote:
>
> mike romain said."I think you have to figure or I do anyway that the advance
> should match
> the 'sweet spot' on the power curve".
> my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
> rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
> that is where I shift if I am accelerating. so with that in mind should I
> install the weaker centrifugal springs(Mr. gasket part # 925d) in the
> distributor. carmine
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
mph with the stock springs in first, then do the same with the heavier
springs.
I don't know what the RV cam runs like, but to get the advance to come
up slower so it peaks at a higher rpm means you need heavier springs or
lighter weights.
Lighter springs will make the advance peak earlier. The weights work
against the springs to advance the timing. Heavier springs means higher
rpm before the weights can stretch them out.
Mike
Jet wrote:
>
> mike romain said."I think you have to figure or I do anyway that the advance
> should match
> the 'sweet spot' on the power curve".
> my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
> rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
> that is where I shift if I am accelerating. so with that in mind should I
> install the weaker centrifugal springs(Mr. gasket part # 925d) in the
> distributor. carmine
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
11-09-2003, 12:08 PM
#36
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
I would find a safe stretch of road and time it from stop up to say 60
mph with the stock springs in first, then do the same with the heavier
springs.
I don't know what the RV cam runs like, but to get the advance to come
up slower so it peaks at a higher rpm means you need heavier springs or
lighter weights.
Lighter springs will make the advance peak earlier. The weights work
against the springs to advance the timing. Heavier springs means higher
rpm before the weights can stretch them out.
Mike
Jet wrote:
>
> mike romain said."I think you have to figure or I do anyway that the advance
> should match
> the 'sweet spot' on the power curve".
> my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
> rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
> that is where I shift if I am accelerating. so with that in mind should I
> install the weaker centrifugal springs(Mr. gasket part # 925d) in the
> distributor. carmine
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
mph with the stock springs in first, then do the same with the heavier
springs.
I don't know what the RV cam runs like, but to get the advance to come
up slower so it peaks at a higher rpm means you need heavier springs or
lighter weights.
Lighter springs will make the advance peak earlier. The weights work
against the springs to advance the timing. Heavier springs means higher
rpm before the weights can stretch them out.
Mike
Jet wrote:
>
> mike romain said."I think you have to figure or I do anyway that the advance
> should match
> the 'sweet spot' on the power curve".
> my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
> rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
> that is where I shift if I am accelerating. so with that in mind should I
> install the weaker centrifugal springs(Mr. gasket part # 925d) in the
> distributor. carmine
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
11-09-2003, 12:08 PM
#37
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
I would find a safe stretch of road and time it from stop up to say 60
mph with the stock springs in first, then do the same with the heavier
springs.
I don't know what the RV cam runs like, but to get the advance to come
up slower so it peaks at a higher rpm means you need heavier springs or
lighter weights.
Lighter springs will make the advance peak earlier. The weights work
against the springs to advance the timing. Heavier springs means higher
rpm before the weights can stretch them out.
Mike
Jet wrote:
>
> mike romain said."I think you have to figure or I do anyway that the advance
> should match
> the 'sweet spot' on the power curve".
> my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
> rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
> that is where I shift if I am accelerating. so with that in mind should I
> install the weaker centrifugal springs(Mr. gasket part # 925d) in the
> distributor. carmine
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
mph with the stock springs in first, then do the same with the heavier
springs.
I don't know what the RV cam runs like, but to get the advance to come
up slower so it peaks at a higher rpm means you need heavier springs or
lighter weights.
Lighter springs will make the advance peak earlier. The weights work
against the springs to advance the timing. Heavier springs means higher
rpm before the weights can stretch them out.
Mike
Jet wrote:
>
> mike romain said."I think you have to figure or I do anyway that the advance
> should match
> the 'sweet spot' on the power curve".
> my motor was rebuilt with a R.V. cam in it that hit peak h.p. at 2800
> rpm's. when I rev it up the motor starts to flatten out at 3000 rpm's and
> that is where I shift if I am accelerating. so with that in mind should I
> install the weaker centrifugal springs(Mr. gasket part # 925d) in the
> distributor. carmine
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:3FAD873F.7063DDE9@sympatico.ca...
> > I think you have to figure or I do anyway that the advance should match
> > the 'sweet spot' on the power curve.
> >
> > These long sixes are low rpm engines with a red line of 4500 that can
> > only be reached if the emissions computer is dead. It tops around 3500
> > with the computer...
> >
> > My engine gets the best gas mileage at this point too and for me 23-2500
> > rpm is where I keep it at 65-70 mph in 4th gear.
> >
> > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the hose
> > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > so I get an instant punch when I floor it, then it mellows a bit as the
> > mechanical weights take over.
> >
> > OEM is a manifold vacuum on the timing with the computer adjusting
> > things on the 258's after 82. It will jump about 15 degrees when you
> > kill the computer and wire the distributor to the ignition module
> > direct.
> >
> > Mike
> >
> > Red Racer wrote:
> > >
> > > Hi Mike,
> > >
> > > If that is the case, Carmine is probably already getting a decent curve.
> > > 2300 is pretty quick for a OEM situation, but all the better as "the
> quicker
> > > the better" is true to an extent. I've worked on many "performance
> motors",
> > > where the mechanical advance was still advancing past 4 grand. That is
> way
> > > to slow, even for a stock motor, irregardless of how many cylinders it
> has.
> > >
> > > Rick
> > >
> > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > Bill, someone or several have told me that the 258 tops out the timing
> > > > around 2300 rpm.
> > > >
> > > > Do you know for sure?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > "L.W.(ßill) ------ III" wrote:
> > > > >
> > > > > Hi Carmine,
> > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > quicker. I believe you'll be happier with the stock springs,
> following
> > > > > your horse power curve, reaching full advance around thirty five
> hundred
> > > > > RPMs. The weaker springs you talk of are for race engines and they
> jump
> > > > > to full advance by two grand, it has an advantage on the drag strip,
> but
> > > > > not for Jeepin'. What I believe is perfect timing is a total of
> thirty
> > > > > eight degrees on the crank. You'll need a special timing light to
> check
> > > > > for total. Or know exactly what your distributor's specs are.
> > > > > God Bless America, ßill O|||||||O
> > > > > mailto:-------------------- http://www.----------.com/
> > > > >
> > > > > Jet wrote:
> > > > > >
> > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> ignition
> > > and a
> > > > > > msd blaster coil. I am wondering what is the tune up speck for my
> set
> > > up.
> > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle. also I
> read
> > > on a
> > > > > > website that when changing to the ford TFI ignition that I could
> put
> > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> timing
> > > advance
> > > > > > to get more advance on high rpm's. should I put the different
> spring
> > > in?
> > > > > > anyone have any advice. carmine
11-09-2003, 10:13 PM
#38
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
It's convoluted a LOT... ;-)
OK, it's late. I'll save your post and analyze it after I get a good
night's sleep.
--
Jim
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FADC553.BAA900BA@sympatico.ca...
> It's convoluted a bit... ;-)
>
> You want the spark to fire in 'advance' of the piston hitting Top Dead
> Center or Before it, so going BTDC is advancing the spark.
>
> I want a stable idle 'advanced' at 9 degrees 'before top dead center'
> with no advance mechanism at all turned on, just where the distributor
> base sets.
>
> To pass emissions this way, the carb needs to be leaned a bit so the
> engine has a rumble to it. If it is purring, it is running too rich for
> the sniffer. I split the difference after the test.
>
> 'Ported' vacuum has no pull with the throttle closed. It sucks from
> above the plate. On the BBD it is near the top on the valve cover side
> and front bottom fender side one too I think.
>
> 'Manifold' vacuum has full pull with the throttle closed. It sucks
> below the carb.
>
> Having the timing advanced at idle will make a lean idle setting on the
> carb purr, so emissions call for it. It loses the vacuum when you punch
> it and starts off slowly/sluggish until the centripetal weights start to
> kick in up in the teens for rpm.
>
> With ported, I get full advance instantly and if I punch it off the line
> it will light up my 33" muds with 3.31 gears turning them.
>
> With ported, the 'advance' advances the timing spark to 'more' advanced
> before top dead center, not advancing above 0 but advancing backward
> before 0.
>
> Basically you sacrifice a bit smoother idle for instant punch and a
> little more noise. I like the noise, it sounds cool coming down
> something steep in gear with the throttle closed. If you are old enough
> to remember muscle cars, they had this 'burble pop pop' sound when the
> engine was doing the braking, same sound.
>
> Mike
>
> TJim wrote:
> >
> > Mike, How do you convert to ported vacuum? They pull in opposite
> > directions. Do you go to port and compensate with the distributor
position?
> > I would think the increase in vacuum on throttle would retard your
> > distributor when you need it to be advancing... ?
> >
> > --
> > Jim
> > --
> > 98 TJ SE
> > 90 SJ GW
> > http://www.delawareja.com/gallery/JDJeep98
> > "You can do any job in the world with the wrong tool if you try hard
> > enough..."
> > "4x4" in caps is "$X$"
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD873F.7063DDE9@sympatico.ca...
> > > I think you have to figure or I do anyway that the advance should
match
> > > the 'sweet spot' on the power curve.
> > >
> > > These long sixes are low rpm engines with a red line of 4500 that can
> > > only be reached if the emissions computer is dead. It tops around
3500
> > > with the computer...
> > >
> > > My engine gets the best gas mileage at this point too and for me
23-2500
> > > rpm is where I keep it at 65-70 mph in 4th gear.
> > >
> > > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the
hose
> > > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > > so I get an instant punch when I floor it, then it mellows a bit as
the
> > > mechanical weights take over.
> > >
> > > OEM is a manifold vacuum on the timing with the computer adjusting
> > > things on the 258's after 82. It will jump about 15 degrees when you
> > > kill the computer and wire the distributor to the ignition module
> > > direct.
> > >
> > > Mike
> > >
> > > Red Racer wrote:
> > > >
> > > > Hi Mike,
> > > >
> > > > If that is the case, Carmine is probably already getting a decent
curve.
> > > > 2300 is pretty quick for a OEM situation, but all the better as "the
> > quicker
> > > > the better" is true to an extent. I've worked on many "performance
> > motors",
> > > > where the mechanical advance was still advancing past 4 grand. That
is
> > way
> > > > to slow, even for a stock motor, irregardless of how many cylinders
it
> > has.
> > > >
> > > > Rick
> > > >
> > > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > > Bill, someone or several have told me that the 258 tops out the
timing
> > > > > around 2300 rpm.
> > > > >
> > > > > Do you know for sure?
> > > > >
> > > > > Mike
> > > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > > 88 Cherokee 235 BFG AT's
> > > > >
> > > > > "L.W.(ßill) ------ III" wrote:
> > > > > >
> > > > > > Hi Carmine,
> > > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > > quicker. I believe you'll be happier with the stock springs,
> > following
> > > > > > your horse power curve, reaching full advance around thirty five
> > hundred
> > > > > > RPMs. The weaker springs you talk of are for race engines and
they
> > jump
> > > > > > to full advance by two grand, it has an advantage on the drag
strip,
> > but
> > > > > > not for Jeepin'. What I believe is perfect timing is a total of
> > thirty
> > > > > > eight degrees on the crank. You'll need a special timing light
to
> > check
> > > > > > for total. Or know exactly what your distributor's specs are.
> > > > > > God Bless America, ßill O|||||||O
> > > > > > mailto:-------------------- http://www.----------.com/
> > > > > >
> > > > > > Jet wrote:
> > > > > > >
> > > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> > ignition
> > > > and a
> > > > > > > msd blaster coil. I am wondering what is the tune up speck for
my
> > set
> > > > up.
> > > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle.
also I
> > read
> > > > on a
> > > > > > > website that when changing to the ford TFI ignition that I
could
> > put
> > > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> > timing
> > > > advance
> > > > > > > to get more advance on high rpm's. should I put the different
> > spring
> > > > in?
> > > > > > > anyone have any advice. carmine
OK, it's late. I'll save your post and analyze it after I get a good
night's sleep.
--
Jim
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FADC553.BAA900BA@sympatico.ca...
> It's convoluted a bit... ;-)
>
> You want the spark to fire in 'advance' of the piston hitting Top Dead
> Center or Before it, so going BTDC is advancing the spark.
>
> I want a stable idle 'advanced' at 9 degrees 'before top dead center'
> with no advance mechanism at all turned on, just where the distributor
> base sets.
>
> To pass emissions this way, the carb needs to be leaned a bit so the
> engine has a rumble to it. If it is purring, it is running too rich for
> the sniffer. I split the difference after the test.
>
> 'Ported' vacuum has no pull with the throttle closed. It sucks from
> above the plate. On the BBD it is near the top on the valve cover side
> and front bottom fender side one too I think.
>
> 'Manifold' vacuum has full pull with the throttle closed. It sucks
> below the carb.
>
> Having the timing advanced at idle will make a lean idle setting on the
> carb purr, so emissions call for it. It loses the vacuum when you punch
> it and starts off slowly/sluggish until the centripetal weights start to
> kick in up in the teens for rpm.
>
> With ported, I get full advance instantly and if I punch it off the line
> it will light up my 33" muds with 3.31 gears turning them.
>
> With ported, the 'advance' advances the timing spark to 'more' advanced
> before top dead center, not advancing above 0 but advancing backward
> before 0.
>
> Basically you sacrifice a bit smoother idle for instant punch and a
> little more noise. I like the noise, it sounds cool coming down
> something steep in gear with the throttle closed. If you are old enough
> to remember muscle cars, they had this 'burble pop pop' sound when the
> engine was doing the braking, same sound.
>
> Mike
>
> TJim wrote:
> >
> > Mike, How do you convert to ported vacuum? They pull in opposite
> > directions. Do you go to port and compensate with the distributor
position?
> > I would think the increase in vacuum on throttle would retard your
> > distributor when you need it to be advancing... ?
> >
> > --
> > Jim
> > --
> > 98 TJ SE
> > 90 SJ GW
> > http://www.delawareja.com/gallery/JDJeep98
> > "You can do any job in the world with the wrong tool if you try hard
> > enough..."
> > "4x4" in caps is "$X$"
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD873F.7063DDE9@sympatico.ca...
> > > I think you have to figure or I do anyway that the advance should
match
> > > the 'sweet spot' on the power curve.
> > >
> > > These long sixes are low rpm engines with a red line of 4500 that can
> > > only be reached if the emissions computer is dead. It tops around
3500
> > > with the computer...
> > >
> > > My engine gets the best gas mileage at this point too and for me
23-2500
> > > rpm is where I keep it at 65-70 mph in 4th gear.
> > >
> > > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the
hose
> > > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > > so I get an instant punch when I floor it, then it mellows a bit as
the
> > > mechanical weights take over.
> > >
> > > OEM is a manifold vacuum on the timing with the computer adjusting
> > > things on the 258's after 82. It will jump about 15 degrees when you
> > > kill the computer and wire the distributor to the ignition module
> > > direct.
> > >
> > > Mike
> > >
> > > Red Racer wrote:
> > > >
> > > > Hi Mike,
> > > >
> > > > If that is the case, Carmine is probably already getting a decent
curve.
> > > > 2300 is pretty quick for a OEM situation, but all the better as "the
> > quicker
> > > > the better" is true to an extent. I've worked on many "performance
> > motors",
> > > > where the mechanical advance was still advancing past 4 grand. That
is
> > way
> > > > to slow, even for a stock motor, irregardless of how many cylinders
it
> > has.
> > > >
> > > > Rick
> > > >
> > > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > > Bill, someone or several have told me that the 258 tops out the
timing
> > > > > around 2300 rpm.
> > > > >
> > > > > Do you know for sure?
> > > > >
> > > > > Mike
> > > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > > 88 Cherokee 235 BFG AT's
> > > > >
> > > > > "L.W.(ßill) ------ III" wrote:
> > > > > >
> > > > > > Hi Carmine,
> > > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > > quicker. I believe you'll be happier with the stock springs,
> > following
> > > > > > your horse power curve, reaching full advance around thirty five
> > hundred
> > > > > > RPMs. The weaker springs you talk of are for race engines and
they
> > jump
> > > > > > to full advance by two grand, it has an advantage on the drag
strip,
> > but
> > > > > > not for Jeepin'. What I believe is perfect timing is a total of
> > thirty
> > > > > > eight degrees on the crank. You'll need a special timing light
to
> > check
> > > > > > for total. Or know exactly what your distributor's specs are.
> > > > > > God Bless America, ßill O|||||||O
> > > > > > mailto:-------------------- http://www.----------.com/
> > > > > >
> > > > > > Jet wrote:
> > > > > > >
> > > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> > ignition
> > > > and a
> > > > > > > msd blaster coil. I am wondering what is the tune up speck for
my
> > set
> > > > up.
> > > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle.
also I
> > read
> > > > on a
> > > > > > > website that when changing to the ford TFI ignition that I
could
> > put
> > > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> > timing
> > > > advance
> > > > > > > to get more advance on high rpm's. should I put the different
> > spring
> > > > in?
> > > > > > > anyone have any advice. carmine
11-09-2003, 10:13 PM
#39
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
It's convoluted a LOT... ;-)
OK, it's late. I'll save your post and analyze it after I get a good
night's sleep.
--
Jim
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FADC553.BAA900BA@sympatico.ca...
> It's convoluted a bit... ;-)
>
> You want the spark to fire in 'advance' of the piston hitting Top Dead
> Center or Before it, so going BTDC is advancing the spark.
>
> I want a stable idle 'advanced' at 9 degrees 'before top dead center'
> with no advance mechanism at all turned on, just where the distributor
> base sets.
>
> To pass emissions this way, the carb needs to be leaned a bit so the
> engine has a rumble to it. If it is purring, it is running too rich for
> the sniffer. I split the difference after the test.
>
> 'Ported' vacuum has no pull with the throttle closed. It sucks from
> above the plate. On the BBD it is near the top on the valve cover side
> and front bottom fender side one too I think.
>
> 'Manifold' vacuum has full pull with the throttle closed. It sucks
> below the carb.
>
> Having the timing advanced at idle will make a lean idle setting on the
> carb purr, so emissions call for it. It loses the vacuum when you punch
> it and starts off slowly/sluggish until the centripetal weights start to
> kick in up in the teens for rpm.
>
> With ported, I get full advance instantly and if I punch it off the line
> it will light up my 33" muds with 3.31 gears turning them.
>
> With ported, the 'advance' advances the timing spark to 'more' advanced
> before top dead center, not advancing above 0 but advancing backward
> before 0.
>
> Basically you sacrifice a bit smoother idle for instant punch and a
> little more noise. I like the noise, it sounds cool coming down
> something steep in gear with the throttle closed. If you are old enough
> to remember muscle cars, they had this 'burble pop pop' sound when the
> engine was doing the braking, same sound.
>
> Mike
>
> TJim wrote:
> >
> > Mike, How do you convert to ported vacuum? They pull in opposite
> > directions. Do you go to port and compensate with the distributor
position?
> > I would think the increase in vacuum on throttle would retard your
> > distributor when you need it to be advancing... ?
> >
> > --
> > Jim
> > --
> > 98 TJ SE
> > 90 SJ GW
> > http://www.delawareja.com/gallery/JDJeep98
> > "You can do any job in the world with the wrong tool if you try hard
> > enough..."
> > "4x4" in caps is "$X$"
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD873F.7063DDE9@sympatico.ca...
> > > I think you have to figure or I do anyway that the advance should
match
> > > the 'sweet spot' on the power curve.
> > >
> > > These long sixes are low rpm engines with a red line of 4500 that can
> > > only be reached if the emissions computer is dead. It tops around
3500
> > > with the computer...
> > >
> > > My engine gets the best gas mileage at this point too and for me
23-2500
> > > rpm is where I keep it at 65-70 mph in 4th gear.
> > >
> > > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the
hose
> > > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > > so I get an instant punch when I floor it, then it mellows a bit as
the
> > > mechanical weights take over.
> > >
> > > OEM is a manifold vacuum on the timing with the computer adjusting
> > > things on the 258's after 82. It will jump about 15 degrees when you
> > > kill the computer and wire the distributor to the ignition module
> > > direct.
> > >
> > > Mike
> > >
> > > Red Racer wrote:
> > > >
> > > > Hi Mike,
> > > >
> > > > If that is the case, Carmine is probably already getting a decent
curve.
> > > > 2300 is pretty quick for a OEM situation, but all the better as "the
> > quicker
> > > > the better" is true to an extent. I've worked on many "performance
> > motors",
> > > > where the mechanical advance was still advancing past 4 grand. That
is
> > way
> > > > to slow, even for a stock motor, irregardless of how many cylinders
it
> > has.
> > > >
> > > > Rick
> > > >
> > > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > > Bill, someone or several have told me that the 258 tops out the
timing
> > > > > around 2300 rpm.
> > > > >
> > > > > Do you know for sure?
> > > > >
> > > > > Mike
> > > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > > 88 Cherokee 235 BFG AT's
> > > > >
> > > > > "L.W.(ßill) ------ III" wrote:
> > > > > >
> > > > > > Hi Carmine,
> > > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > > quicker. I believe you'll be happier with the stock springs,
> > following
> > > > > > your horse power curve, reaching full advance around thirty five
> > hundred
> > > > > > RPMs. The weaker springs you talk of are for race engines and
they
> > jump
> > > > > > to full advance by two grand, it has an advantage on the drag
strip,
> > but
> > > > > > not for Jeepin'. What I believe is perfect timing is a total of
> > thirty
> > > > > > eight degrees on the crank. You'll need a special timing light
to
> > check
> > > > > > for total. Or know exactly what your distributor's specs are.
> > > > > > God Bless America, ßill O|||||||O
> > > > > > mailto:-------------------- http://www.----------.com/
> > > > > >
> > > > > > Jet wrote:
> > > > > > >
> > > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> > ignition
> > > > and a
> > > > > > > msd blaster coil. I am wondering what is the tune up speck for
my
> > set
> > > > up.
> > > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle.
also I
> > read
> > > > on a
> > > > > > > website that when changing to the ford TFI ignition that I
could
> > put
> > > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> > timing
> > > > advance
> > > > > > > to get more advance on high rpm's. should I put the different
> > spring
> > > > in?
> > > > > > > anyone have any advice. carmine
OK, it's late. I'll save your post and analyze it after I get a good
night's sleep.
--
Jim
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FADC553.BAA900BA@sympatico.ca...
> It's convoluted a bit... ;-)
>
> You want the spark to fire in 'advance' of the piston hitting Top Dead
> Center or Before it, so going BTDC is advancing the spark.
>
> I want a stable idle 'advanced' at 9 degrees 'before top dead center'
> with no advance mechanism at all turned on, just where the distributor
> base sets.
>
> To pass emissions this way, the carb needs to be leaned a bit so the
> engine has a rumble to it. If it is purring, it is running too rich for
> the sniffer. I split the difference after the test.
>
> 'Ported' vacuum has no pull with the throttle closed. It sucks from
> above the plate. On the BBD it is near the top on the valve cover side
> and front bottom fender side one too I think.
>
> 'Manifold' vacuum has full pull with the throttle closed. It sucks
> below the carb.
>
> Having the timing advanced at idle will make a lean idle setting on the
> carb purr, so emissions call for it. It loses the vacuum when you punch
> it and starts off slowly/sluggish until the centripetal weights start to
> kick in up in the teens for rpm.
>
> With ported, I get full advance instantly and if I punch it off the line
> it will light up my 33" muds with 3.31 gears turning them.
>
> With ported, the 'advance' advances the timing spark to 'more' advanced
> before top dead center, not advancing above 0 but advancing backward
> before 0.
>
> Basically you sacrifice a bit smoother idle for instant punch and a
> little more noise. I like the noise, it sounds cool coming down
> something steep in gear with the throttle closed. If you are old enough
> to remember muscle cars, they had this 'burble pop pop' sound when the
> engine was doing the braking, same sound.
>
> Mike
>
> TJim wrote:
> >
> > Mike, How do you convert to ported vacuum? They pull in opposite
> > directions. Do you go to port and compensate with the distributor
position?
> > I would think the increase in vacuum on throttle would retard your
> > distributor when you need it to be advancing... ?
> >
> > --
> > Jim
> > --
> > 98 TJ SE
> > 90 SJ GW
> > http://www.delawareja.com/gallery/JDJeep98
> > "You can do any job in the world with the wrong tool if you try hard
> > enough..."
> > "4x4" in caps is "$X$"
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD873F.7063DDE9@sympatico.ca...
> > > I think you have to figure or I do anyway that the advance should
match
> > > the 'sweet spot' on the power curve.
> > >
> > > These long sixes are low rpm engines with a red line of 4500 that can
> > > only be reached if the emissions computer is dead. It tops around
3500
> > > with the computer...
> > >
> > > My engine gets the best gas mileage at this point too and for me
23-2500
> > > rpm is where I keep it at 65-70 mph in 4th gear.
> > >
> > > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the
hose
> > > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > > so I get an instant punch when I floor it, then it mellows a bit as
the
> > > mechanical weights take over.
> > >
> > > OEM is a manifold vacuum on the timing with the computer adjusting
> > > things on the 258's after 82. It will jump about 15 degrees when you
> > > kill the computer and wire the distributor to the ignition module
> > > direct.
> > >
> > > Mike
> > >
> > > Red Racer wrote:
> > > >
> > > > Hi Mike,
> > > >
> > > > If that is the case, Carmine is probably already getting a decent
curve.
> > > > 2300 is pretty quick for a OEM situation, but all the better as "the
> > quicker
> > > > the better" is true to an extent. I've worked on many "performance
> > motors",
> > > > where the mechanical advance was still advancing past 4 grand. That
is
> > way
> > > > to slow, even for a stock motor, irregardless of how many cylinders
it
> > has.
> > > >
> > > > Rick
> > > >
> > > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > > Bill, someone or several have told me that the 258 tops out the
timing
> > > > > around 2300 rpm.
> > > > >
> > > > > Do you know for sure?
> > > > >
> > > > > Mike
> > > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > > 88 Cherokee 235 BFG AT's
> > > > >
> > > > > "L.W.(ßill) ------ III" wrote:
> > > > > >
> > > > > > Hi Carmine,
> > > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > > quicker. I believe you'll be happier with the stock springs,
> > following
> > > > > > your horse power curve, reaching full advance around thirty five
> > hundred
> > > > > > RPMs. The weaker springs you talk of are for race engines and
they
> > jump
> > > > > > to full advance by two grand, it has an advantage on the drag
strip,
> > but
> > > > > > not for Jeepin'. What I believe is perfect timing is a total of
> > thirty
> > > > > > eight degrees on the crank. You'll need a special timing light
to
> > check
> > > > > > for total. Or know exactly what your distributor's specs are.
> > > > > > God Bless America, ßill O|||||||O
> > > > > > mailto:-------------------- http://www.----------.com/
> > > > > >
> > > > > > Jet wrote:
> > > > > > >
> > > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> > ignition
> > > > and a
> > > > > > > msd blaster coil. I am wondering what is the tune up speck for
my
> > set
> > > > up.
> > > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle.
also I
> > read
> > > > on a
> > > > > > > website that when changing to the ford TFI ignition that I
could
> > put
> > > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> > timing
> > > > advance
> > > > > > > to get more advance on high rpm's. should I put the different
> > spring
> > > > in?
> > > > > > > anyone have any advice. carmine
11-09-2003, 10:13 PM
#40
Guest
Posts: n/a
Re: tune up speck on a 86 cj7
It's convoluted a LOT... ;-)
OK, it's late. I'll save your post and analyze it after I get a good
night's sleep.
--
Jim
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FADC553.BAA900BA@sympatico.ca...
> It's convoluted a bit... ;-)
>
> You want the spark to fire in 'advance' of the piston hitting Top Dead
> Center or Before it, so going BTDC is advancing the spark.
>
> I want a stable idle 'advanced' at 9 degrees 'before top dead center'
> with no advance mechanism at all turned on, just where the distributor
> base sets.
>
> To pass emissions this way, the carb needs to be leaned a bit so the
> engine has a rumble to it. If it is purring, it is running too rich for
> the sniffer. I split the difference after the test.
>
> 'Ported' vacuum has no pull with the throttle closed. It sucks from
> above the plate. On the BBD it is near the top on the valve cover side
> and front bottom fender side one too I think.
>
> 'Manifold' vacuum has full pull with the throttle closed. It sucks
> below the carb.
>
> Having the timing advanced at idle will make a lean idle setting on the
> carb purr, so emissions call for it. It loses the vacuum when you punch
> it and starts off slowly/sluggish until the centripetal weights start to
> kick in up in the teens for rpm.
>
> With ported, I get full advance instantly and if I punch it off the line
> it will light up my 33" muds with 3.31 gears turning them.
>
> With ported, the 'advance' advances the timing spark to 'more' advanced
> before top dead center, not advancing above 0 but advancing backward
> before 0.
>
> Basically you sacrifice a bit smoother idle for instant punch and a
> little more noise. I like the noise, it sounds cool coming down
> something steep in gear with the throttle closed. If you are old enough
> to remember muscle cars, they had this 'burble pop pop' sound when the
> engine was doing the braking, same sound.
>
> Mike
>
> TJim wrote:
> >
> > Mike, How do you convert to ported vacuum? They pull in opposite
> > directions. Do you go to port and compensate with the distributor
position?
> > I would think the increase in vacuum on throttle would retard your
> > distributor when you need it to be advancing... ?
> >
> > --
> > Jim
> > --
> > 98 TJ SE
> > 90 SJ GW
> > http://www.delawareja.com/gallery/JDJeep98
> > "You can do any job in the world with the wrong tool if you try hard
> > enough..."
> > "4x4" in caps is "$X$"
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD873F.7063DDE9@sympatico.ca...
> > > I think you have to figure or I do anyway that the advance should
match
> > > the 'sweet spot' on the power curve.
> > >
> > > These long sixes are low rpm engines with a red line of 4500 that can
> > > only be reached if the emissions computer is dead. It tops around
3500
> > > with the computer...
> > >
> > > My engine gets the best gas mileage at this point too and for me
23-2500
> > > rpm is where I keep it at 65-70 mph in 4th gear.
> > >
> > > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the
hose
> > > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > > so I get an instant punch when I floor it, then it mellows a bit as
the
> > > mechanical weights take over.
> > >
> > > OEM is a manifold vacuum on the timing with the computer adjusting
> > > things on the 258's after 82. It will jump about 15 degrees when you
> > > kill the computer and wire the distributor to the ignition module
> > > direct.
> > >
> > > Mike
> > >
> > > Red Racer wrote:
> > > >
> > > > Hi Mike,
> > > >
> > > > If that is the case, Carmine is probably already getting a decent
curve.
> > > > 2300 is pretty quick for a OEM situation, but all the better as "the
> > quicker
> > > > the better" is true to an extent. I've worked on many "performance
> > motors",
> > > > where the mechanical advance was still advancing past 4 grand. That
is
> > way
> > > > to slow, even for a stock motor, irregardless of how many cylinders
it
> > has.
> > > >
> > > > Rick
> > > >
> > > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > > Bill, someone or several have told me that the 258 tops out the
timing
> > > > > around 2300 rpm.
> > > > >
> > > > > Do you know for sure?
> > > > >
> > > > > Mike
> > > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > > 88 Cherokee 235 BFG AT's
> > > > >
> > > > > "L.W.(ßill) ------ III" wrote:
> > > > > >
> > > > > > Hi Carmine,
> > > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > > quicker. I believe you'll be happier with the stock springs,
> > following
> > > > > > your horse power curve, reaching full advance around thirty five
> > hundred
> > > > > > RPMs. The weaker springs you talk of are for race engines and
they
> > jump
> > > > > > to full advance by two grand, it has an advantage on the drag
strip,
> > but
> > > > > > not for Jeepin'. What I believe is perfect timing is a total of
> > thirty
> > > > > > eight degrees on the crank. You'll need a special timing light
to
> > check
> > > > > > for total. Or know exactly what your distributor's specs are.
> > > > > > God Bless America, ßill O|||||||O
> > > > > > mailto:-------------------- http://www.----------.com/
> > > > > >
> > > > > > Jet wrote:
> > > > > > >
> > > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> > ignition
> > > > and a
> > > > > > > msd blaster coil. I am wondering what is the tune up speck for
my
> > set
> > > > up.
> > > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle.
also I
> > read
> > > > on a
> > > > > > > website that when changing to the ford TFI ignition that I
could
> > put
> > > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> > timing
> > > > advance
> > > > > > > to get more advance on high rpm's. should I put the different
> > spring
> > > > in?
> > > > > > > anyone have any advice. carmine
OK, it's late. I'll save your post and analyze it after I get a good
night's sleep.
--
Jim
"Mike Romain" <romainm@sympatico.ca> wrote in message
news:3FADC553.BAA900BA@sympatico.ca...
> It's convoluted a bit... ;-)
>
> You want the spark to fire in 'advance' of the piston hitting Top Dead
> Center or Before it, so going BTDC is advancing the spark.
>
> I want a stable idle 'advanced' at 9 degrees 'before top dead center'
> with no advance mechanism at all turned on, just where the distributor
> base sets.
>
> To pass emissions this way, the carb needs to be leaned a bit so the
> engine has a rumble to it. If it is purring, it is running too rich for
> the sniffer. I split the difference after the test.
>
> 'Ported' vacuum has no pull with the throttle closed. It sucks from
> above the plate. On the BBD it is near the top on the valve cover side
> and front bottom fender side one too I think.
>
> 'Manifold' vacuum has full pull with the throttle closed. It sucks
> below the carb.
>
> Having the timing advanced at idle will make a lean idle setting on the
> carb purr, so emissions call for it. It loses the vacuum when you punch
> it and starts off slowly/sluggish until the centripetal weights start to
> kick in up in the teens for rpm.
>
> With ported, I get full advance instantly and if I punch it off the line
> it will light up my 33" muds with 3.31 gears turning them.
>
> With ported, the 'advance' advances the timing spark to 'more' advanced
> before top dead center, not advancing above 0 but advancing backward
> before 0.
>
> Basically you sacrifice a bit smoother idle for instant punch and a
> little more noise. I like the noise, it sounds cool coming down
> something steep in gear with the throttle closed. If you are old enough
> to remember muscle cars, they had this 'burble pop pop' sound when the
> engine was doing the braking, same sound.
>
> Mike
>
> TJim wrote:
> >
> > Mike, How do you convert to ported vacuum? They pull in opposite
> > directions. Do you go to port and compensate with the distributor
position?
> > I would think the increase in vacuum on throttle would retard your
> > distributor when you need it to be advancing... ?
> >
> > --
> > Jim
> > --
> > 98 TJ SE
> > 90 SJ GW
> > http://www.delawareja.com/gallery/JDJeep98
> > "You can do any job in the world with the wrong tool if you try hard
> > enough..."
> > "4x4" in caps is "$X$"
> >
> > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > news:3FAD873F.7063DDE9@sympatico.ca...
> > > I think you have to figure or I do anyway that the advance should
match
> > > the 'sweet spot' on the power curve.
> > >
> > > These long sixes are low rpm engines with a red line of 4500 that can
> > > only be reached if the emissions computer is dead. It tops around
3500
> > > with the computer...
> > >
> > > My engine gets the best gas mileage at this point too and for me
23-2500
> > > rpm is where I keep it at 65-70 mph in 4th gear.
> > >
> > > I run a ported vacuum with 750 rpm idle set at 9 deg BTDC (with the
hose
> > > off, sometimes ported can suck a bit at idle, I don't take the chance)
> > > so I get an instant punch when I floor it, then it mellows a bit as
the
> > > mechanical weights take over.
> > >
> > > OEM is a manifold vacuum on the timing with the computer adjusting
> > > things on the 258's after 82. It will jump about 15 degrees when you
> > > kill the computer and wire the distributor to the ignition module
> > > direct.
> > >
> > > Mike
> > >
> > > Red Racer wrote:
> > > >
> > > > Hi Mike,
> > > >
> > > > If that is the case, Carmine is probably already getting a decent
curve.
> > > > 2300 is pretty quick for a OEM situation, but all the better as "the
> > quicker
> > > > the better" is true to an extent. I've worked on many "performance
> > motors",
> > > > where the mechanical advance was still advancing past 4 grand. That
is
> > way
> > > > to slow, even for a stock motor, irregardless of how many cylinders
it
> > has.
> > > >
> > > > Rick
> > > >
> > > > "Mike Romain" <romainm@sympatico.ca> wrote in message
> > > > news:3FAD2064.60008CFE@sympatico.ca...
> > > > > Bill, someone or several have told me that the 258 tops out the
timing
> > > > > around 2300 rpm.
> > > > >
> > > > > Do you know for sure?
> > > > >
> > > > > Mike
> > > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > > 88 Cherokee 235 BFG AT's
> > > > >
> > > > > "L.W.(ßill) ------ III" wrote:
> > > > > >
> > > > > > Hi Carmine,
> > > > > > It's HEI (High Energy Ignition) It's not more advance, it's
> > > > > > quicker. I believe you'll be happier with the stock springs,
> > following
> > > > > > your horse power curve, reaching full advance around thirty five
> > hundred
> > > > > > RPMs. The weaker springs you talk of are for race engines and
they
> > jump
> > > > > > to full advance by two grand, it has an advantage on the drag
strip,
> > but
> > > > > > not for Jeepin'. What I believe is perfect timing is a total of
> > thirty
> > > > > > eight degrees on the crank. You'll need a special timing light
to
> > check
> > > > > > for total. Or know exactly what your distributor's specs are.
> > > > > > God Bless America, ßill O|||||||O
> > > > > > mailto:-------------------- http://www.----------.com/
> > > > > >
> > > > > > Jet wrote:
> > > > > > >
> > > > > > > I have a 86 cj7 with a 258 no emissions, Weber carb TFI ford
> > ignition
> > > > and a
> > > > > > > msd blaster coil. I am wondering what is the tune up speck for
my
> > set
> > > > up.
> > > > > > > timing for 87 octane and 93 octane, idle rpm's, fast idle.
also I
> > read
> > > > on a
> > > > > > > website that when changing to the ford TFI ignition that I
could
> > put
> > > > > > > different spring (Mr. gasket part # 925d) in the centrifugal
> > timing
> > > > advance
> > > > > > > to get more advance on high rpm's. should I put the different
> > spring
> > > > in?
> > > > > > > anyone have any advice. carmine
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